Questions About Gooseneck Loosestrife

Indianapolis residence – I inherited some of this invasive plant, thought I had dug it all out a couple years ago, but this year it’s back alongside the house like gangbusters!

Answered by Heather on June 18, 2011Certified Expert

A.

Yes, it is known for that. Any small pieces of the root will result in this plant coming back.

Persistence is the key with getting rid of it. Dig it up as best you can and then treat the area with boiling water. Please note that boiling water will kill any plant that it comes in contact with, so don't get any on any plants you would like to keep.

After this, keep a sharp eye out for any stray sprouts and pull these as soon as you spot them.

If it is an area you don't mind fallow for a bit, you can also smother the plants with thick layers of newspaper or cardboard.

I planted 2 plants about five years ago and they have taken over my garden! The roots spread out in a complex network and even encroach on my lawn and have invaded my Hosta. How do I get rid of it?

Thank you.

Answered by Downtoearthdigs on April 18, 2016Certified Expert

A.

You will need to use a Glyphosate herbicide to kill Loosestrife.
It is however, non-selective and will kill other plants that it touches.
Careful application of the herbicide is very important to protect your other plants.

Go the the garden store and get an herbicide that has the chemical, glyphosate, in it (such as 'Roundup'). I've found it cheaper to buy the glyphosate as a concentrate so that I can mix a lot of it at home in my two-gallon hand sprayer. Pick a warm, windless, and rain-free day and very carefully but thoroughly spray the gooseneck loosestrife with the glyphosate. Be very careful not to spray any plants that you want to keep. Glyphosate will kill just about any plant it touches if enough of it gets on them. However, with gooseneck loosestrife, you may have to make several applications throughout the growing season. Wait at least a week before applying glyphosate again if you didn't get all of it the first time.

Can I keep it in a container after I cut it back? Does it spread a lot?

Thanks.

Answered by Alisma on November 9, 2016Certified Expert

A.

You can certainly dig up a clump of the plant and place it in a container with potting soil. Yes, it does spread a lot. It is considered to have an invasive root system and may be banned in certain areas:

You say it should be divided ever so often. I wish that was my problem, instead it has taken over a large area in my flower garden. Started digging it up but it is impossible to get all the roots, they go deep and spread. what can I do to open up my garden again?

Answered by Downtoearthdigs on June 21, 2017Certified Expert

A.

Yes, in some regions it can become invasive or aggressive.
Glyphosate herbicides are very effective for killing loosestrife. Glyphosate is available under the trade name Roundup. Glyphosate is nonselective; however, selective application techniques allow it to be used effectively with minimum damage to desirable plants. It is taken up through the leaves or young stems and will kill any plant that it is applied to. Therefore, treat only the loosestrife plants and avoid contact with valuable plants.https://www.gardeningknowhow.com/ornamental/flowers/gooseneck-loosestrife/gooseneck-loosestrife-flowers.htm